﻿using System;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;

namespace VK.Comm
{
    public static class Thumbnail
    {
        /// <summary>
        /// 生成缩略图
        /// </summary>
        /// <param name="originalImagePath">源图路径（物理路径）</param>
        /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
        /// <param name="width">缩略图宽度</param>
        /// <param name="height">缩略图高度</param>
        /// <param name="mode">生成缩略图的方式</param>
        /// <param name="fileExt">图片后缀名加.</param>
        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, Mode mode, string fileExt)
        {
            System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

            int towidth = width;
            int toheight = height;

            int x = 0, y = 0;
            int ow = originalImage.Width;
            int oh = originalImage.Height;
            int drawx = 0, drawy = 0;


            //新建一个bmp图片
            System.Drawing.Image bitmap = null;

            switch (mode)
            {
                case Mode.Fix:
                    bitmap = new System.Drawing.Bitmap(width, height);
                    break;
                case Mode.Auto:
                    if (width >= height)
                    {
                        toheight = originalImage.Height * width / originalImage.Width;
                    }
                    else
                    {
                        towidth = originalImage.Width * height / originalImage.Height;
                    }
                    bitmap = new System.Drawing.Bitmap(towidth, toheight);
                    break;
                case Mode.Cut:
                    if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                    {
                        oh = originalImage.Height;
                        ow = originalImage.Height * towidth / toheight;
                        y = 0;
                        x = (originalImage.Width - ow) / 2;
                    }
                    else
                    {
                        ow = originalImage.Width;
                        oh = originalImage.Width * height / towidth;
                        x = 0;
                        y = (originalImage.Height - oh) / 2;
                    }
                    bitmap = new System.Drawing.Bitmap(towidth, toheight);
                    break;
                case Mode.Fill:
                    int cwidth = width - originalImage.Width;
                    int cheight = height - originalImage.Height;
                    if (cwidth >= 0 && cheight >= 0)
                    {
                        //放大
                        if (cwidth >= cheight)
                        {
                            double bl = (double)height / (double)originalImage.Height;
                            towidth = (int)(originalImage.Width * bl);
                            toheight = (int)(originalImage.Height * bl);
                            drawx = (width - towidth) / 2;
                        }
                        else
                        {
                            double bl = (double)width / (double)originalImage.Width;
                            towidth = (int)(originalImage.Width * bl);
                            toheight = (int)(originalImage.Height * bl);
                            drawy = (height - toheight) / 2;
                        }
                    }
                    else
                    {
                        //缩小
                        if (cwidth >= cheight)
                        {
                            double bl = (double)height / (double)originalImage.Height;
                            towidth = (int)(originalImage.Width * bl);
                            toheight = (int)(originalImage.Height * bl);
                            drawx = (width - towidth) / 2;
                        }
                        else
                        {
                            double bl = (double)width / (double)originalImage.Width;
                            towidth = (int)(originalImage.Width * bl);
                            toheight = (int)(originalImage.Height * bl);
                            drawy = (height - toheight) / 2;
                        }
                    }

                    bitmap = new System.Drawing.Bitmap(width, height);
                    break;
                default:
                    break;
            }

            //新建一个画板
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);

            //设置图像质量
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
            //清空画布并以白色背景色填充 透明：Transparent
            g.Clear(System.Drawing.Color.White);

            //在指定位置并且按指定大小绘制原图片的指定部分
            g.DrawImage(originalImage, new System.Drawing.Rectangle(drawx, drawy, towidth, toheight),
                 new System.Drawing.Rectangle(x, y, ow, oh),
                 System.Drawing.GraphicsUnit.Pixel);

            try
            {
                switch (fileExt)
                {
                    case ".gif":
                        bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Gif);
                        break;
                    case ".jpeg":
                        bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
                        break;
                    case ".jpg":
                        bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
                        break;
                    case ".png":
                        bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Png);
                        break;
                    default:
                        bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
                        break;
                }
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }

        /// <summary>
        /// 在图片上增加文字水印
        /// </summary>
        /// <param name="Path">原服务器图片路径</param>
        /// <param name="Path_sy">生成的带文字水印的图片路径</param>
        public static void AddWatermarkText(string Path, string Path_sy)
        {
            string addText = "测试水印";
            System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
            g.DrawImage(image, 0, 0, image.Width, image.Height);
            System.Drawing.Font f = new System.Drawing.Font("Verdana", 16);
            System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.Blue);

            g.DrawString(addText, f, b, 15, 15);
            g.Dispose();

            image.Save(Path_sy, System.Drawing.Imaging.ImageFormat.Jpeg);
            image.Dispose();
        }

        /// <summary>
        /// 在图片上生成图片水印
        /// </summary>
        /// <param name="Path">原服务器图片路径</param>
        /// <param name="Path_syp">生成的带图片水印的图片路径</param>
        /// <param name="Path_sypf">水印图片路径</param>
        public static void AddWatermarkImage(string Path, string Path_syp, string Path_sypf)
        {
            System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
            System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Path_sypf);
            System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(image);
            float[][] ptsArray ={ 
	                    new float[] {1, 0, 0, 0, 0},
                        new float[] {0, 1, 0, 0, 0},
                        new float[] {0, 0, 1, 0, 0},
                        new float[] {0, 0, 0, 0.4f, 0}, //注意：此处为0.25f，图像为半透明
                        new float[] {0, 0, 0, 0, 1}};
            ColorMatrix clrMatrix = new ColorMatrix(ptsArray);
            ImageAttributes imgAttributes = new ImageAttributes();
            //设置图像的颜色属性
            imgAttributes.SetColorMatrix(clrMatrix, ColorMatrixFlag.Default,
            ColorAdjustType.Bitmap);
            g.DrawImage(copyImage,
                new System.Drawing.Rectangle(image.Width - copyImage.Width, image.Height - copyImage.Height, copyImage.Width, copyImage.Height),
                0,
                0,
                copyImage.Width,
                copyImage.Height,
                System.Drawing.GraphicsUnit.Pixel,
                imgAttributes);
            g.Dispose();

            image.Save(Path_syp, System.Drawing.Imaging.ImageFormat.Jpeg);
            image.Dispose();
        }

        public enum Mode
        {
            /// <summary>
            /// 指定高宽缩放（可能变形）
            /// </summary>
            Fix = 1,
            /// <summary>
            /// 高宽比例不变，按照大的一方为准（不变形）
            /// </summary>
            Auto = 2,
            /// <summary>
            /// 指定高宽裁减（不变形）
            /// </summary>
            Cut = 3,
            /// <summary>
            /// 规定高宽，填充白色背景（不变形）
            /// </summary>
            Fill = 4
        }
    }
}
